The Case of the Disappearing Aluminum

Introduction:
Welcome to the case of the disappearing aluminum. We are going to determine the number of grams of copper that will be produced from an oxidation reduction reaction when you know the mass of Aluminum that reacted with a known amount of Copper (II) Sulfate pentahydrate and to compare this to the actual yield of copper. We will find the theoretical yield and then actual yield, thus giving us the percent yield. We will then conclude the lab.

Materials

• Aluminum Powder
• Copper (II) Sulfate
• Water
• Filter paper
• Scale
• Bunsen Burner
• Beaker

Safety: Aprons, goggles, forceps

Procedure:

1. Obtained a beaker
2. Added 90 mL of water to the beaker
3. Measured out 9.17 g of Copper (II) Sulfate to the water and began heating it on the bunson burner
4. Measured out .989 g of Aluminum powder
5. Stirred the Copper (II) Sulfate until dissolved, then added the aluminum powder
6. Continued heating until all was dissolved.
7. Filtered out the residue in a funnel
8. Cleaned equipment and put residue out to dry
9. Weighed residue
10. Found limiting reactant, theoretical yield, then compare to actual yield and that to find the percent yield.
11. Cleaned up and completed lab

Data Table

Item	Mass
Aluminum Powder	.989 g
Copper Sulfate	9.17 g
Coffee Filter	.89 g
Product + Filter Paper	3.4 g
Product (Copper)	2.51 g

Results:

Balanced Equation: 3Cu(II)SO₄ + 2Al --- 3Cu + Al₂(SO₄)₃

Limiting Reactant: Al

Actual Yield: 2.51 g of Cu

Theoretical Yield: 3.48 g of Cu

Percent Yield: 72%

Discussion: This was a lab that was meant to find the percent yield of the product. There were many steps in determining this. First by weighing the product we found the actual yield (2.51 g of Copper), then we found the limiting reactant which was aluminum and that led us to the theoretical yield of 3.48 g of Copper. We divided the actual by the theoretical and got 72%, which is not too bad meaning we did not waste the much in the reaction process. This was a single displacement reaction, because aluminum replaced copper in the the copper sulfate to make aluminum sulfate and copper was left as a precipitate. The formation of the precipitate and color change into red meant that it was indeed a chemical reaction.

Conclusion:
This lab created copper which we used to calculate several things. It helped us understand the percent yield, and it showed us how much is wasted because the actual yield is always less then the theoretical yield. We explored a way to calculate this by creating copper from copper sulfate and aluminum powder mixed together in water. It was a unique experience that helped put percent yield and chemical reactions on a visual scale. We got 72% of the theoretical yield in the actual, so we were pretty close, but there are some reasons that we did not get near the full amount. Perhaps the actual measurement was not as exact as it could of been, not all the copper precipitate might of been filtered out, perhaps there was some left in the copper aluminum solution, and a variety of other possible explanations. In short, our lab was a very informative lab, and helped us learn a lot about percent yield, theoretical yield, actual yield, and how they all relate to each other. The End.

Types of Reactions.

By: Daniel and Kody

• Introduction/Background: There are five types of chemical reactions in chemistry. There is single displacement, double displacement, decomposition, synthesis, and combustion.

1. Single displacement involves two elements swapping spots in the product. One example is 2AL+3CuCl₂ ---- 2AlCl₃ +3Cu
2. Double displacement is a chemical reaction in which ions from two compounds interact in solution to form a product. One example is 2KL+Pb(NO₃ )_{2 -------} PbI₂ + 2KNO₃
3. Decomposition is a chemical reaction in which a single compound is broken down to produce two or more simpler substances. One example is

   CH₃OH ----- CO + 2H₂

4. Synthesis is a chemical reaction in which atoms or simple molecules combine to form a compound that is more complex. One example is

   6CO₂+6H₂O ---- C₆H₁₂O₆ + 6O₂

5. Combustion is a violent exothermic reaction, usually with oxygen, to form oxides. Carbon dioxide and water are always products. One example is

   C₂H₄ + 2O₂ ----- 2H₂O + CO₂

• The purpose of this lab is to observe different types of chemical reactions and record our observations and what kind of reactions they were. Then we have to write the balanced equations of each reaction.

• Procedure:
1. We obtained 3 small test tubes.
2. In the first test tube, we placed a piece of zince and about 1/2 mL of copper sulfate solution. We recorded our observations
3. In the second test tube we added about 1/2 mL Barium Nitrate solution to about of 1/2 mL of copper sulfate. We recorded our observations.
4. In the third test tube we placed a piece of magnesium ribbon. We added about 1/2 mL of HCl solution. We recorded observations.
   
5. We lighted a bunsen burner (burning propane gas, C₃H₈). We recorded observations of the flame.
6. We rinsed out the first test tube. Add about 2 mL Hydrogen Peroxide solution. We lightly heated it, and recorded our observations.
7. We added a pinched of Manganese (IV) oxide to the hydrogen Peroxide solution. Then we lightly heated it, and we recorded our observations

1. Safety Procedures:
• Apply goggles
• Apply apron
• Use test tube clamps
  

• Data Table Click on Table
• Data Analysis: The various types of reactions with their balanced equations are in the above data table. All types of reactions were present except for a synthesis reaction. Perhaps if we were to do this lab again we would try a synthesis or direct combination, as the old schoolers call it, reaction. This lab helped us identify what the types of reactions look like and how to properly balance them. This lab was quite informative
• Conclusion- The first reaction was a single displacement because a metal zinc replaced the metal copper in the product. The second reaction was a double displacement because two molecules switched position in the final product, the nitrate and the sulfate. In reaction 3 magnesium replaces hydrogen in the chemical reaction. In reaction five it is a combustion reaction because it is a hydrocarbon reacting with an oxygen to release carbon dioxide and water. The final reaction reaction is a decomposition reaction because the hydrogen peroxide breaks down into water and carbon dioxide. These are the types of reactions and why they are classified as so.
  

Polarity and Molecular Shape Lab

Lewis Structures and Ball/Stick Models


Triangular Planar, 90-109.5, non-polar




Tetrahedron, 109.5, non-polar




Trianguler Planar, 109.5, non-polar



Octahedral, 90, non-polar



Tetrahedral, 109.5, non-polar


Linear, 90-109.5, polar



Tetrahedral, 109.5, non-polar

Daniel Webster
Kody Berget

Polarity and Molecular Shape Lab

A. Statement of the Problem
1. How shape affects polarity
2. How to make ball/stick models of Lewis structures of molecular formula

We know that a molecules electronegativity difference affects it's polarity. Now we are going to see how an atom's shape affects it so, by contructing ball/stick models based on the Lewis structures of the molescules


B. Hypothesis
1. I hypothesize that the shape of the covalently bonded molecule will affect the polarity of the molecule. I will build ball/stick models to help prove this. I know that electronegativity difference affects a molecules polarity, and I will find if the shape of a molecule will.

C. Objectives
1. Construct models of molecules from their Lewis Structures
2. Determine polarity of molecules
3. Predict polarity of molecules
D. Procedure
1. Built model for each of the listed molecules on the data table and drew the Lewis structures.
2.. Drew the structures on the paper, using solid lines to represent bonds in the plane of the paper, and dashed lines for bonds that point back or forward from the plane of the paper.
3. Determined whether the molecular shape, bond angle, if its polar or not, and resonance.
4. Materials:










E. Results
1. The pictures of the models are in the above section.
2.



















Conclusion:

The shape does affect the polarity of the model, and a molecule must have two halves to be polar, one negative and one positive. The real difference thought between polar and non-polar molecules lies in the electronegativity difference, which also affects the orientation of the molecules shapes and angles. In conclusion, this lab was really helpful way to help us understand a molecules shape, and its polarity.

1)Explain how water's shape causes it to be polar
The two ends are both positive and and the shape is not linear, but bent.
2)Describes how water's properties would be different if the molecules were linear instead of bent.
It would probably be less polar, and the shape would of course be linear.

Discussion:
Daniel: This lab really helped us understand Lewis structure and shapes in covalent molecules. It helped us understand the relation between an atoms shape and its polarity. In another lab, we could also shape ionic molecules to help us understand the difference between the two types of molecules, and maybe next time use an electonegativity chart to help us with our lab.
Kody: In addition to what Daniel said I would like to note how this lab really help me, being a kid with ADD. The book stuff really didn't click to good for me, I mean I understood it for the most part but not 100 percent. When we did this lab it was some hands on learning so I found it to be more easily understood.

We are determining what solvent is most polar with the overhead pens
• What solvent is more polar or adhesive?
• What colors are pure substances or mixtures?
• What solvent reacts best to separate the colors?

We know that chromatography paper is used to separate the components of a liquid so that it can be identified. The dissolved colors move up the paper according to how well they attract to it or how adhesive the liquid is.


We hypothesized that H20 would be the most adhesive liquid because we weren’t sure what the other liquids were and we knew H20 was a polar fluid.

Materials we used in our lab:
• 9 strips of chromatography paper.
• Overhead pens: Red, Purple, Blue, Yellow, Orange, Green.
• Solvents H2O, CH3OH, C3H7OH, and C6H14
• 24 Well plate.
• Paper Towels
• Apron
• Goggles
• Notebooks

We used chemicals that could be hazardous to our skin and eyes. So we wore aprons and goggles. We also had fume hood vent so that we did not breath in the fumes the solvents let off.


Our Procedure started putting our safety equipment on such as our aprons and goggles. Then we cut 4 pieces of chromatography paper in the same lengths. We then made creases ¼ of the way up the paper and dabbed the black over head pen 4 times across the crease. We then filled our 24 well plate with the four solvents. We dipped the strips into the solvents making sure not to put the dot into the solvent but enough to let it wick up the paper. We waited 30 minutes and then recorded our results in our notebooks. H2O carried the ink farthest. So we agreed to use this for the next part of the lab. Repeat steps leading up to creasing the papers. This time you dot the separate papers with Red, purple, blue, green, orange, and yellow ink. We then filled the 24 well plate with H2O. We dipped the papers into the solvent and waited 30 minutes. Then we recorded our results in our notebooks. (See Results)




Results/Data:

Our hypothesis proved to be correct that H2O was the best solvent because it had the greatest polarity.
• Results: Water worked the best as the solvent then CH3OH came in second, then C3H7OH, and C6H14 was the worst solvent. The yellow color we used is a pure substance and the green, blue, red, and orange were mixtures.
• We learned that chromatography paper could separate components so they can be identified.
• Possible errors could be our chromatography paper being dipped to far into the solvent.